class_docstr: TempCopy is a class that you can use as a context manager to transfer files
  into the local directory with either
  
  - a name specified by you, or
  - an autogenerated name.
  
  Supply a dictionary mapping your files => your requested filename (or None).
  When used as a context manager, TempCopy will
  
  - copy data from every source to every destination
  - return a dictionary of the source you provided => the destination's path in
    the local directory.
  
  The temporary files will live inside the current directory where python's
  being executed for the duration of TempCopy's scope.
  
  We did NOT use a tmp directory here because the changing UUID name
  invalidates the docker image each time a new temp path / directory is
  generated.
  
  mapping: dict mapping from optional src to optional destination filename. The
           source should be a relative or absolute path on the local machine.
           The destination should be a current-directory-local path, NOT an
           absolute path. If a key is None, nothing will happen.
  
  Returns:
  dict of each non-None key in mapping => the destination's relative path in
  the local directory.
docstr: If the context manager is holding on to temporary files, delete them all and
  reset the internal state.
docstr_tok: ["If","the","context","manager","is","holding","on","to","temporary","files",",","delete","them","all","and","reset","the","internal","state","."]
code: def __exit__(self, exc_type, exc_val, exc_tb):
      """If the context manager is holding on to temporary files, delete them all and
      reset the internal state.
  
      """
      if self._written is not None:
          for _, dst in self._written.items():
              if os.path.exists(dst):
                  os.remove(dst)
          self._written = None
  
imports: import io
  import os
  import shutil
  import socket
  import subprocess
  import sys
  import time
  import uuid
  from itertools import chain
  from typing import Dict, List, NamedTuple, Optional, Tuple
  from blessings import Terminal
label_desc: Use image node_id 7 for calling the TempCopy obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_val, exc_tb) without return types